【作者】 江照意；

【导师】 彭群生；

【作者基本信息】 浙江大学 ， 计算机图形学， 2007， 博士

【摘要】 红外成像制导具有在黑暗环境中目标识别能力强、能夜间打击目标、制导精度高和很强的抗干扰能力等特点，已成为现代精确制导武器的重要组成部分。在红外成像制导武器的研制过程中，需要提供大量的各种场景的红外图像作为输入进行测试。然而，现场实拍得到的只是当时气象条件下的红外图像，并不能表达其它气象条件下的红外场景，若全部实拍需要耗费很长的时间及大量的人力物力，况且许多军事目标是无法拍摄到的。而红外成像仿真技术可为解决这类问题提供一种极为有效、经济的途径，对现代精确制导武器的开发和研制来说具有十分重要的意义。本文围绕典型目标场景的红外成像仿真，对建筑物、桥梁／水面和铁道等典型目标场景红外成像热模型的建立及其场景的红外图像绘制、红外热像系统自动增益和偏移的调整及其大气传输和红外成像系统效应的模拟展开深入的研究。与传统方法不同的是，我们综合了传热学、红外物理和计算机图形学等学科的相关知识，着眼于红外成像仿真的热模型的建立和红外真实感绘制，并利用图形硬件(GPU)进行高质量的快速仿真。在本文的第二章中，我们对建筑物场景的红外真实感成像进行了探讨。根据能量守恒定律建立建筑物外表面的热量平衡方程，采用有限容积法求解外表面的温度场，提出了一个基于物理的红外仿真热模型；在图像分割和红外材质库的基础上，提出了一种由可见光图像生成红外纹理图像的方法；根据红外辐射的原理，重点考虑太阳辐射的影响，把问题简化为固定轨道上的线性光源的光照问题，采用遮挡区间预计算和GPU加速，提出了一种有效的建筑物场景的红外阴影快速绘制算法。桥梁目标的红外特征分析在军事交通领域具有特别重要的意义。本文第三章通过分析桥梁的热过程，使用有限容积法建立桥梁的热平衡方程，经过附加源项和局部线性化处理，得到一个具有统一形式的离散线性方程组，采用交替方向隐式方法(ADI)求解温度场，生成桥梁的红外图像；考虑了水体本身的吸热(或放热)和有效发射率的方向性，提出了一个改进的水面红外辐射计算模型，利用JONSWAP功率谱模型获取水面的高度场，提出了一个基于“不变网格映射”的GPU加速绘制算法，生成桥梁和水面场景的红外合成图像，从而实现了桥梁和水面场景的红外成像仿真。铁路轨道目前仍是交通运输的大动脉，而考虑大气传输和成像系统效应的铁路场景红外成像仿真的研究尚很少有人涉及。本文第四章的前半部分我们分析了影响钢轨发射率大小的因素，提出了一个简化的铁道温度场计算模型，根据发射率的方向性绘制出铁路场景的红外图像；并采用基于温度窗的控制方法，用来模拟红外热像系统随场景变化而自动调整增益和偏移，以使高动态范围的红外图像能进行自适应显示；本章的后半部分，提出了一个基于预计算和MTF相结合的红外辐射大气传输模型，模拟大气的衰减和模糊效应；并采用基于调制传递函数的方法模拟光学系统和探测器的效应。在本文的最后，作者对本文的研究工作进行总结，并提出进一步的研究方向。更多还原

【Abstract】 Infrared(IR) imaging guiding have been an important role for developing modern military equipment with precision guiding, because it has incredible ability at correct identifying targets and anti-jamming in bad weather. Lots of various IR images are needed during the development of weapon with IR imaging guiding. However, real images from IR camera can’t satisfy all the demand in testing because we can’t provide with all possible IR images in different meteorologic conditions. And taking real images needs more times, lots of manpower and material resources. IR imaging simulation is an effective and economical solution for the previous problem. It plays a key role during developing and manufacture of weapon with IR imaging guiding.This paper focuses on thermal model and infrared image synthesis for typical target scenes, including building, bridge, water and railway. We simulate the modulating process of display scenes with high dynamic range. The mechanism of air transmission and infrared imaging system is also simulated for imroveing the realistic synthesis. Differing from the traditional methods, we integrate the knowledge of heat transfer, infrared physics and computer graphics. Thermal model of simulation and realistic rendering in IR band is focused on. And modern graphic hardware (GPU) is used for accelerating the high-quality rendering process.In simulation of building scene, we establish a thermal equilibrium equation according to conservation of energy at first, which is solved using finite volume method. So the thermal model is build. Second we produce an infrared texture image from a corresponding visible image based on segment of visible image and infrared material library. Finally we propose a shadow rendering algorithm based on occlusion interval using GPU. Occlusion interval is used to pre-calculate the information of visibility. Owing to the main contribution of sun, we focus on the radiance from sun which is considered as a linear light source running at fixed orbit.In simulation of bridge and water scene, we firstly build the thermal model for bridge based on analyzing its thermal process and finite volume method. Through additive source item and local linearization processing, the linear equations with unified form is obtained. Alternating direction implicit(ADI) method is used to solve the equations, the temperature distribution of bridge is gained. Then we render the IR image of bridge according to the temperature distribution. Secondly, we put forward an improved temperature calculation model for water surface. The direction of effective emissivity and quality of heat stored (or released) by water body is considered in this model. Then the surface height field of water is computed with the JONSWAP power spectral formulation. Finally a GPU-accelerated rendering scheme based on persistent grid mapping(PGM) is designed to simulate the scene including bridge and water.In simulation of railway scene, a simple numeric model is proposed to calculate the temperature distribution of railway. We mainly focus on the emissivtiy of steel track, which is small and vary with its surface status. Then a control method based on the concept of temperature window is employed to simulate the auto gain and offset of IR imaging system. So image with high dynamic range is displayed adaptively. The attenuation and blurring effect of atmosphere is simulated by combined the pre-calculate using PcModWin with modulation transfer function(MTF). Finally the effect of optic system and detector is simulated by their MTEAt last, we draw a conclusion of this paper and propose some opportunities in future work.更多还原